if your tires are currently underinflated, getting proper, or overinflation will of course affect MPG, other than that. hooie.
there is not available power for most racers in the pits, and aircompressors are difficult to move around. a single 3000psi cyllinder could keep tires and tools running for weeks.
the water vapor quetion removed by the compressor so mostly dry air in tires, water vapor is negligible. oxygen can cause tires to deteriorate, but they still contact air on outside of tire... so only the higher pressure air inside tire... hmm. highpressure oxygen could be damaging the tire... nahh, I don't buy it.
I will dump all the air I can out of my tires...and inflate with N2, since I have a cyllinder. but I doubt it will make any diff. I have all mileage records for the last 3 years on my suburban. lets see if it changes at all.
John